Summary of Significant Accounting Policies and Recent Accounting Pronouncements - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2018 Segment
Summary Of Significant Accounting Policies [Line Items]
Number of operating segments	1
Product Revenues [Member] | Customer One [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	44.00%
Product Revenues [Member] | Customer Two [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	35.00%
Product Revenues [Member] | Customer Three [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	19.00%
Accounts Receivable [Member] | Customer One [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	61.00%
Accounts Receivable [Member] | Customer Two [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	26.00%
Accounts Receivable [Member] | Customer Three [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	11.00%
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable payment term	30 days
Minimum [Member] | Outside of U.S. [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable payment term	45 days
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable payment term	60 days
Maximum [Member] | Outside of U.S. [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable payment term	120 days